sim: fix frame metadata MSB problem

sim_pipeline.py

@@ -5,6 +5,8 @@ from misoc.cores.liteeth_mini.mac.crc import LiteEthMACCRCEngine
 
 from src.gateware.cxp_pipeline import *
 
+from types import SimpleNamespace
+
 class EOP_Marker(Module):
     def __init__(self):
         self.sink = stream.Endpoint(word_layout_dchar)
@@ -276,7 +278,7 @@ class Frame_Extractor(Module):
         self.new_line = Signal()
 
         n_metadata_chars = 23
-        self.metadata = Record([
+        img_header_layout = [
             ("stream_id", char_width),
             ("source_tag", 2*char_width), 
             ("x_size", 3*char_width), 
@@ -287,8 +289,9 @@ class Frame_Extractor(Module):
             ("pixel_format", 2*char_width), 
             ("tap_geo", 2*char_width), 
             ("flag", char_width), 
-        ])
-        assert len(self.metadata.raw_bits()) == n_metadata_chars*char_width  
+        ]
+        assert layout_len(img_header_layout) == n_metadata_chars*char_width  
+
 
         # # #
 
@@ -332,7 +335,7 @@ class Frame_Extractor(Module):
                     type["new_frame"]: [
                         self.new_frame.eq(1),
                         NextValue(cnt, cnt.reset),
-                        NextState("GET_STREAM_ID"),
+                        NextState("GET_FRAME_DATA"),
                     ],
                     type["line_break"]: [
                         self.new_line.eq(1),
@@ -347,11 +350,12 @@ class Frame_Extractor(Module):
             )
         )
 
+        packet_buffer = Signal(layout_len(img_header_layout))
         case = dict(
-            (i, NextValue(self.metadata.raw_bits()[8*i:8*(i+1)], self.sink.dchar))
+            (i, NextValue(packet_buffer[8*i:8*(i+1)], self.sink.dchar))
             for i in range(n_metadata_chars)
         )
-        fsm.act("GET_STREAM_ID",
+        fsm.act("GET_FRAME_DATA",
             self.sink.ack.eq(1),
             If(self.sink.stb,
                 Case(cnt, case),
@@ -364,6 +368,13 @@ class Frame_Extractor(Module):
             ),
         )
 
+        # dissect packet 
+        self.metadata = SimpleNamespace()
+        idx = 0
+        for name, size in img_header_layout:
+            # CXP use MSB even when sending duplicate chars
+            setattr(self.metadata, name, reverse_bytes(packet_buffer[idx:idx+size]))
+            idx += size
 
 
 class Pixel_Decoder(Module):